A phase I study of natural killer (NK) cell infusion in patients with recurrent hepatocellular carcinoma (HCC) after liver transplantation reported tolerability and preliminary antitumor signals. The trial, led by researchers including Yang and Gong, focused on a high‑risk population where recurrence after transplant is a major clinical challenge. Investigators emphasized the therapy’s potential for immune-based control of recurrent disease with an acceptable safety profile in the transplant setting, but called for larger trials to establish efficacy, dosing strategies, and long-term outcomes.